/**
 * ============================================================================
 * INVEZTHINK - Standardized Button System
 * ============================================================================
 * Single source of truth for all button styles across the application.
 * Replaces fragmented inline button definitions in HTML files.
 * 
 * USAGE:
 * - Primary CTA:   <button class="btn-primary">Sign Up</button>
 * - Secondary:     <button class="btn-secondary">Learn More</button>
 * - Outline:       <button class="btn-outline">View Details</button>
 * - Large variant: <button class="btn-primary btn-large">Get Started</button>
 * - Small variant: <button class="btn-primary btn-small">Try Now</button>
 * 
 * VARIANTS:
 * - .btn-large:  Increased padding for hero CTAs
 * - .btn-small:  Compact size for inline actions
 * - :disabled:   Automatic disabled state styling
 * ============================================================================
 */

:root {
    /* Button Colors */
    --btn-primary-bg: linear-gradient(135deg, #3B82F6 0%, #2563EB 100%);
    --btn-primary-hover: linear-gradient(135deg, #2563EB 0%, #1D4ED8 100%);
    --btn-primary-shadow: rgba(59, 130, 246, 0.3);
    
    --btn-secondary-bg: rgba(255, 255, 255, 0.05);
    --btn-secondary-border: rgba(255, 255, 255, 0.1);
    --btn-secondary-hover-bg: rgba(255, 255, 255, 0.08);
    --btn-secondary-hover-border: #3B82F6;
    
    --btn-outline-border: #3B82F6;
    --btn-outline-hover-bg: rgba(59, 130, 246, 0.1);
    
    --btn-disabled-bg: #374151;
    --btn-disabled-text: #6B7280;
}

/* ============================================================================
   BASE BUTTON STYLES (Shared)
   ============================================================================ */
.btn-primary,
.btn-secondary,
.btn-outline,
.btn-large,
.btn-small {
    /* Layout */
    display: inline-block;
    text-align: center;
    text-decoration: none;
    
    /* Typography */
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    line-height: 1.5;
    
    /* Interaction */
    cursor: pointer;
    user-select: none;
    
    /* Transitions */
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Borders */
    border: none;
    outline: none;
}

/* ============================================================================
   PRIMARY BUTTON (Main CTAs)
   ============================================================================ */
.btn-primary {
    background: var(--btn-primary-bg);
    color: white;
    padding: 12px 32px;
    border-radius: 10px;
    font-size: 15px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.btn-primary:hover {
    background: var(--btn-primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--btn-primary-shadow);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 6px var(--btn-primary-shadow);
}

.btn-primary:disabled {
    background: var(--btn-disabled-bg);
    color: var(--btn-disabled-text);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* ============================================================================
   SECONDARY BUTTON (Alternative actions)
   ============================================================================ */
.btn-secondary {
    background: var(--btn-secondary-bg);
    border: 1px solid var(--btn-secondary-border);
    color: white;
    padding: 11px 31px; /* 1px less to account for border */
    border-radius: 10px;
    font-size: 15px;
}

.btn-secondary:hover {
    background: var(--btn-secondary-hover-bg);
    border-color: var(--btn-secondary-hover-border);
    transform: translateY(-1px);
}

.btn-secondary:active {
    transform: translateY(0);
}

.btn-secondary:disabled {
    background: transparent;
    border-color: var(--btn-disabled-bg);
    color: var(--btn-disabled-text);
    cursor: not-allowed;
    transform: none;
}

/* ============================================================================
   OUTLINE BUTTON (Subtle actions)
   ============================================================================ */
.btn-outline {
    background: transparent;
    border: 2px solid var(--btn-outline-border);
    color: var(--btn-outline-border);
    padding: 10px 30px; /* 2px less to account for border */
    border-radius: 10px;
    font-size: 15px;
}

.btn-outline:hover {
    background: var(--btn-outline-hover-bg);
    border-color: #2563EB;
    color: #2563EB;
}

.btn-outline:active {
    background: rgba(59, 130, 246, 0.15);
}

.btn-outline:disabled {
    border-color: var(--btn-disabled-bg);
    color: var(--btn-disabled-text);
    cursor: not-allowed;
    background: transparent;
}

/* ============================================================================
   SIZE VARIANTS
   ============================================================================ */

/* Large Buttons (Hero CTAs) */
.btn-large {
    padding: 16px 40px;
    font-size: 16px;
    border-radius: 12px;
}

.btn-large.btn-secondary {
    padding: 15px 39px;
}

.btn-large.btn-outline {
    padding: 14px 38px;
}

/* Small Buttons (Inline actions) */
.btn-small {
    padding: 8px 20px;
    font-size: 13px;
    border-radius: 8px;
}

.btn-small.btn-secondary {
    padding: 7px 19px;
}

.btn-small.btn-outline {
    padding: 6px 18px;
}

/* ============================================================================
   ICON BUTTONS (Globe, Theme switcher, etc.)
   ============================================================================ */
.icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: 1px solid var(--btn-secondary-border);
    border-radius: 8px;
    color: white;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.icon-btn:hover {
    background: var(--btn-secondary-hover-bg);
    border-color: var(--btn-secondary-hover-border);
    transform: scale(1.05);
}

.icon-btn:active {
    transform: scale(0.95);
}

/* ============================================================================
   RESPONSIVE ADJUSTMENTS
   ============================================================================ */
@media (max-width: 768px) {
    /* Reduce button padding on mobile */
    .btn-primary,
    .btn-secondary,
    .btn-outline {
        padding: 10px 24px;
        font-size: 14px;
    }
    
    .btn-large {
        padding: 14px 32px;
        font-size: 15px;
    }
    
    .btn-small {
        padding: 7px 16px;
        font-size: 12px;
    }
    
    .icon-btn {
        width: 36px;
        height: 36px;
        font-size: 16px;
    }
}

/* ============================================================================
   ACCESSIBILITY
   ============================================================================ */

/* Focus states for keyboard navigation */
.btn-primary:focus-visible,
.btn-secondary:focus-visible,
.btn-outline:focus-visible,
.icon-btn:focus-visible {
    outline: 2px solid #3B82F6;
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .btn-primary {
        border: 2px solid white;
    }
    
    .btn-secondary {
        border-width: 2px;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    .btn-primary,
    .btn-secondary,
    .btn-outline,
    .icon-btn {
        transition: none;
        transform: none !important;
    }
}